Windows 7: Windows 7 and torrents

Hello all,

Im new to the forums here and i searched around a while, but i cant seem to find a fix for my problem.

Im a pc engineer, so hardware and software problems are my job. but me and even my collegues are baffled by this problem.

I have an asus p5k for a while now. And started with Windows xp.
never had any problems.
Then i went over to Vista. well, we all know vista
Then i installed Windows 7 when it came out. And all worked perfect.

Then i moved to Japan and took my pc there. reassembled it just like it was back in Holland and it seemed to be fine. no reinstall, all same hardware.
But in japan, i noticed that when downloading with any torrent program would freeze up the whole system. this means programs like Utorrent, but also any game client. Such as the final fantasy 14 beta, aion, and any other game that uses torrents to update itself.
After any torrent is active, it randomly hangs up the pc after some minutes.
Back in Holland now, i reinstalled Windows 7 ultimate 64 bit. and the problem remained. Every torrent freezes the system even after a clean install.
I installed windows xp along with windows 7, and when running windows xp on the same system, same partitioned hdd there are not problems at all. it only appears in windows 7 so it is not a hardware problem.

I have the Asus p5k network drivers installed, the Vista 64bit drivers in compatibility mode, but also tried the drivers windows installs itself. both have the exact same problem.

Im at a loss now, as i really dont want to have to restart my pc, download in windows xp, then reboot again and run the dowloaded files in 7.
There has to be some kind of fix for this?